next generation nuclear physics
DESCRIPTION
Next Generation Nuclear Physics. Barbara Jacak Stony Brook April 7, 2006. QCD with nuclei as the laboratory colliders to explore the frontiers of high temperature and high density. QCD lab at BNL. High Temperature limit of QCD: HI collisions at RHIC High Density limit: - PowerPoint PPT PresentationTRANSCRIPT
Next Generation Nuclear Physics
QCD with nuclei as the laboratory
colliders to explore the frontiers of high temperature and high density
QCD lab at BNL
High Temperature limit of QCD: HI collisions at RHIC
High Density limit:electron-ion colliderreach very small x
non-perturbative QCD:large-scale computing resources: QCDOC +…
T>200 MeV
A Unique Evolution
QCD
confinement new phases
low xcolor glass
High T, QCD
p-spinstructure
RHIC RHIC upgrades eRHIC
Discovery Exploration Precision
QCD phase transition at high T
Color charge of gluons self-interaction theory is non-abelian
confinement of quarks in hadrons
at large distance:
+ +…
At high temperature and density: force is screened by produced color-chargesexpect transition to plasma of (free?) quarks and gluons
asymptotic freedom
4 complementary experiments at RHIC
STAR
We have found really surprising stuff!
Pressure built up very rapidly during ion collisions at RHIC large collective flowhydrodynamics works w/low viscosityinteraction large, fast thermalizationviscosity small
huge energy loss in fast quarks
traversing mediumenergy, gluon density largemedium is opaque
3x higher baryon yield than p+p
Kolb, et al
Not the expected ideal gas!!
PHENIX
fast equilibration, flow, opacity – how?
parton cascade using free q,g scattering cross sections doesn’t work! need x50 in medium
Molnar
Lattice QCD shows qqresonant states at T > Tc, also implying high interaction cross sections
Hatsuda, et al.
see something like this in EM plasma!
visc
osit
y
coupling = <PE>/<KE>
S. Ichimaru
strong coupling
do heavy quarks also lose energy and flow?
seems so, but cannot be all by radiating gluons
e± from charm show non-zero flow
thermalization with the light quarks?not so easy to do!
large mass → produced earlysets scale for interaction w/QGP
so…
How do we study the plasma physics of this stuff?
hint:how are electromagnetic (normal) plasmas studied?
Plasma properties studied by plasma physicists
density and opacity seen to be high at RHIC
transport properties of the plasmaelectrical and thermal conductivityhydrodynamic expansion, shock propagation, diffusionwaves in plasma and dispersion relationplasma oscillations and instabilitiesscreening length
radiation (temperature, dynamics, bound states…)blackbody radiation from plasmabremsstrahlungcollisions and recombination in the plasma
So, here’s a plan
1) Upgrade RHIC detectorsrare and/or high background probes of plasmaQGP plasma a “filter” for fragmentation, confinement
2) Increase RHIC luminosity hard probes cross sections small at √s=200 GeVscan beam energy, size in lifetime of a grad student!x40 compared to baseline (x10 by electron cooling)
Add electron accelerator (either ring or linac)reach very high gluon densities - saturation?
probe with DISstudy role of quarks, gluons in nucleon spin structure
reach very low-x, with high luminosity
Detector upgrades to address key measurements
Electromagnetic radiation → plasma temperaturesignal electron
Cherenkov blobs
partner positronneeded for rejection e+
e-
pair opening angle
e+e- pair continuum
background: e+ e -
e+ e -
photon detection byCsI-coated triple GEMs
will be installed in PHENIX in 2007
correlations of ≥ 2 particles from jets traversing QGP-jet correlations; fixes jet energyidentify the fragments for hadronization, charm e-loss
upgrade PID(STAR), coverage(PHENIX) & luminosity!
Jet tomography (jet-jet and -jet) → plasma transport
major upgrades, continued
Heavy flavor (c- and b-production)
D
AuAu D
X
J/B
X
K
ee
add Si vertextrackers to STAR (thinned wafers)PHENIX (strips, pixels)
RHIC (1.5 nb-1) RHIC upgrade (30 nb-1)J/y (y’) 38,000 (1400) 760,000 (28,000) 35 700
•Quarkonia need luminosity!
W-Physics upgrades for q,qbar spin contribution
Forward GEM Tracker
Heavy Flavor Tracker
Inner Silicon Tracker
Forward Silicon Tracker
STAR: Tracking UpgradeR&D ongoing
PHENIX: muon triggerfunded by NSF
R1
R2
R3
RHIC II
FY 2006 FY 2007 FY 2008 FY 2009 FY 2010 FY 2011 FY 2012 FY 2013
RHIC Mid-Term Strategic Plan
LHI
LP4
e Cooling CD-0 CD-1 CD-2 CD-3 CD-4
PHENIX + STAR Data-Taking
Hi Rate DAQ 1000
PIDHBD
TOF
VTX
Forward
FMSMu Trigger Nose Cone Calorimeter
EBIS
Heavy Ion Luminosity
SPIN F.O.M.
e-pair spectrum Open Charm Jet Tomography
Mono-JetU+U
PHENIX STAR
G/G P-V W± prod. and Transversity
PHENIX & STAR VTX upgrades
STAR Integrated Tracking
Scientific Frontiers for eRHIC
Understand nucleon structure and its spin, role of quarks & gluons in the nucleons, issues of confinement, low-x & DVCS…
Determine the role of partons in nuclei to understand confinement in nuclei
Study hadronization in nucleons & in nuclear media
Explore partonic matter under extreme conditions with e-A Large “A” at RHIC : very high gluon densitiesSaturation/Color Glass Condensate
EIC detector
central tracking:high precision, fast Si (inner) triple-GEM (outer)
Collisionsystem
<L>/L0
(%)
107
Run time
(s/year)
L0
(cm-2s-1)
√sNN
(TeV)
1034 * 14.0
pp
70-50 106 ** 7.71027 5.5PbPb
Running parameters:
geom
(b)
0.07
Other collision systems:pA, lighter ions (Sn, Kr, Ar, O) and energies
*Lmax(ALICE) = 1031 ** Lint(ALICE) ~ 0.7 nb-1/year
Further pushing the high T limit:the LHC as a heavy ion collider
ALICE: the dedicated HI experiment
Solenoid magnet 0.5 T
Central tracking system:• ITS •TPC• TRD• TOF
MUON Spectrometer:• absorbers• tracking stations• trigger chambers• dipole
ALICE Tracking
Combined tracking efficiency and momentum resolution
Challenges for TPCs in high luminosity A+A
event pile-uppattern recognition problem gets “interesting”
space chargefield distortion effect upon momentum reconstruction
can the compact TPC ideas be practical and efficient for the huge multiplicities of heavy ion collisions?
Upgrades High T QCD…. QGP Spin Low-x
PHENIX
e+e- heavy jet quarkonia
flavor tomog.
W ΔG/G
Hadron blind detector
Vertex Tracker
Muon Trigger
Forward cal. (NCC)
X
X X O O
O
O O
X
X
O
O
X
STAR
Time of Flight (TOF)
MicroVtx (HFT)
Forward Tracker
Forward Cal (FMS)
DAQ 1000
O X O
X X
O
O X X
X O
O
O O
X
O
RHIC Luminosity O O X X O O O
RHIC Upgrades Overview
X upgrade critical for successO upgrade significantly enhances program
A. Drees 4/4/05
Goal:q andq spin structure of the nucleonUse pp → W+X
Challenges:nb cross section: run pp at 500 GeV
with high luminosity and polarizationReduce MHz interaction rate → few
kHz event rate Unambiguous identification of W+,W
Detector upgrades:PHENIX: high pT single muon
triggerSTAR: tracking upgrade
Spin Structure of the Proton: W physics
d (u)
u ( d)
W
Forward Physics Upgrades: 1<<3
PHENIX: forward calorimeterR&D ongoing
STAR: forward meson calorimeterProposal submitted to NSF
what is a plasma?
4th state of matter (after solid, liquid and gas)
a plasma is:ionized gas which is macroscopically neutral
(not neutral on scale of interparticle distance)exhibits collective effects
interactions among charges of multiple particlesspreads charge out into characteristic (Debye) length, D
multiple particles inside this lengththey screen each other
plasma size > D
Where the QCD plasma physics fits in
high energy density: > 1011 J/m3
P > 1 MbarI > 3 X 1015W/cm2 Fields > 500 Tesla
is QGP a strongly coupled plasma?
Huge gluon density! estimate = <PE>/<KE>
using QCD coupling strength g<PE>=g2/d d ~1/(41/3T)
<KE> ~ 3T ~ g2 (41/3T) / 3Tg2 ~ 4-6 (value runs with T)
for T=200 MeV plasma parameter
quark gluon plasma should be a strongly coupled plasma
how does it compare to interesting EM plasmas?
> 1: strongly coupled, few particles inside Debye radius
more sophisticated
see Markus Thomas hep-ph/0503154
getting the units right… = 2Cg2/4dT
get ~ 1.5 – 5 at T=200 MeVNB: magnetic interaction is ~ comparable to electric
interaction in a relativistic plasmarange from uncertainties in g2 and Casimirs
A (supersymmetric) pseudo-QCD theory can be mapped to a 10-dimensional classical gravity theory on the background of black 3-branes
The calculation can be performed there as the absorption of gravitons by the braneTHE SHEAR VISCOSITY OF STRONGLY COUPLED N=4 SUPERSYMMETRIC YANG-MILLS PLASMA., G.
Policastro, D.T. Son , A.O. Starinets, Phys.Rev.Lett.87:081601,2001 hep-th/0104066
gives = (h/4) S known liquids, even He, are above this!
seems to be a perfect fluid (not quite sci-fi!)
would like tocalculate:
this is hard!
for strongly coupled EM plasmas
kinetic energy distribution (T)measure electrons radiated from plasma
flow properties (turbulent and non)particle transport via laser-induced flourescenceagain study electron radiation from plasmaopacity to hard x-rays (time resolved)
thermalization timephoton absorption & ion spectrum vs. time
plasma oscillations see density fluctuations in electron arrival times
correlations among particlesmeasure radiated particle pairs
crystallization viscosity
M.Miller, QM04
(1/N
trig)d
N/d
()
STAR Preliminary
cGeVp
cGevpassocT
trigT
/42.0
/64
speed of sound via a density wave?
+/-1.23=1.91,4.37 → cs ~ 0.33 (√0.33 in QGP, 0.2 in hadron gas)
PHENIX preliminary
dN
/d(
)
g radiates energykick particles in the plasmaaccelerate them along the jet
Jet tomography
correlations of 2, 3 (more?) particles from jets traversing medium
-jet correlations; fixes jet energygq → q
identify the hadrons: hadronization, charm e-loss
increase PHENIX, STAR calorimeter coverage for
upgrade rate capabilities of data acquisition, analysis2007
increased machine luminosity (2013?)
cross section small, so rate is low
why so many baryons at medium pT?
sensitive probe of hadronizationquark coalescence: good starting point
small production rate → sensitivity to correlations of quarks inside the medium!a tool to probe wakes in the plasma. correlators?
upgrade PID in STAR and PHENIX by ‘09 increased luminosity to allow scanning collision energy,
species (Au+Au, Cu+Cu compare to p+p, d+Au)
jet
par
tner
s p
ertr
igge
r
Npartp+p
all baryons from quarks drawn from the medium
dileptons and photons
pT spectrum of soft * reflects Tinitial
interpretation problem: unfolding time history of the expansionnote: fixing the EOS for hydro is essential!
medium modificationof final vector mesons
decays of bound states?
detector upgrades will reduce decay background and allow measurement of charm background
energy & system size scans require luminosity upgrade
Heavy Quarkonium – a screening probe
map charmonium and bottomonium states to study competition between melting and regeneration
color screening length? Tinitial? upgraded luminosity will allow:
measurement of Y v2 of J/energy scan for J/, screening vs. regeneration
RHIC
counts per yearcomparable to thoseat LHC!
why do we need high luminosity?
QCD analogy to hard x-ray probes in plasma physics?for opacity studies & Thomson scattering-> monoenergetic hard colored probe
achievable via g-jet coincidences, binned in g energy
QCD analogy to probes of screening lengthJ/psi suppression via screening c-cbar bound state?
very confusing at the moment!need more theory and data
QCD analogy to plasma shots with different conditionsscan in energy and system size
measure opacity, elliptic flow, charm, g-jet
Heavy Quarks – open charm
precision measurements to quantify energy loss and v2 as a function of momentumhow opaque IS the medium?relative role of gluon radiation and collisional energy loss
must measure charm yieldto subtract from intermediate mass dilepton continuum
inner tracker upgrades for PHENIX and STAR needed to tag displaced vertex for clean measurement
ready by 2011
what sQGP plasma properties could these yield?
speed of sound via jet modifications quark correlations in the medium
baryon formationmedium modifications of jet fragmentation
propagation of jet-induced shocks constrain radiative vs. collisional energy loss screening length via onium spectroscopy T via radiated dileptons, photons dissipation via energy flow in shocked medium Would like to identify experimental signatures of
viscosityWeibel instability in first 0.6 fm/c
look for the jet on the other sideSTAR PRL 90, 082302 (2003)
Central Au + Au
Peripheral Au + Au
Medium is opaque!
Are back-to-back jets there in d+Au?
Pedestal&flow subtracted
Yes!
no medium ↓
no jet quenching
At RHIC:
CuCu
200 GeV/c
AuAu
200 GeV/c
dAu
200 GeV/c
J/ muon arm
1.2 < |y| < 2.2
mea
sure
d/e
xpec
ted
At RHIC:
CuCu
200 GeV/c
AuAu
200 GeV/c
dAu
200 GeV/c
AuAuee
200 GeV/c
CuCuee
200 GeV/c
J/ muon arm
1.2 < |y| < 2.2
J/ eeCentral arm
-0.35 < y < 0.35
At RHIC:
CuCu
200 GeV/c
AuAu
200 GeV/c
dAu
200 GeV/c
AuAuee
200 GeV/c
CuCu
62 GeV/c
J/ muon arm
1.2 < |y| < 2.2
J/ eeCentral arm
-0.35 < y < 0.35
Factor ~3suppression
in central events
CuCuee
200 GeV/c
At RHIC:
J/ muon arm
1.2 < |y| < 2.2
J/ eeCentral arm
-0.35 < y < 0.35
Factor ~3suppression
in central events
Data show the same trend within errors for all beams and even at √s=62 GeV
RAA
vs Npart
: PHENIX and NA50
NA50 data normalized at NA50 p+p point.
Suppression similar in the two experiments, although the collision energy is 10 times higher (200GeV in PHENIX & 17GeV in NA50)
What suppression should we expect?
Models that were successful in describing SPS datafail to describe data at RHIC
- too much suppression -
can get better agreement with data
if add formation of “extra” J/ by coalescence of c and anti-c from the plasma
caveat: not necessarily unique or correct explanation!
Possibility of plasma instability → anisotropy
small deBroglie wavelength q,g point sources for g fieldsgluon fields obey Maxwell’s equationsadd initial anisotropy and you’d expect Weibel instability
moving charged particles induce B fieldsB field traps soft particles moving in A directiontrapped particle’s current reinforces trapping B fieldcan get exponential growth
(e.g. causes filamentation of beams) could also happen to gluon fields early in Au+Au collision
timescale short compared to QGP lifetimebut gluon-gluon interactions may cause instability to
saturate → drives system to isotropy & thermalization
The vision of a QCD laboratory
QCD Laboratory at BNLA place to do e-p, e-A, p-A, p-p & A-A collisions &
multiple detectors and Lattice QCD computing facility
explore zero and high temperature QCD at limits of our
knowledge nucleon spin structure in its entirety using hadronic
and leptonic probes
A. Deshpande (SBU/RBRC) & Richard Milner (MIT) the advisors for the eRHIC
B. Jacak (SBU) and John Harris (Yale) for A-A experiments in the next decade
non-perturbative QCD – lattice gauge theory
T/Tc
Karsch, Laermann, Peikert ‘99
/T4
Tc ~ 170 ± 10 MeV (1012 °K)
~ 3 GeV/fm3
required conditions to create quark gluon plasma in lab
~15% from ideal gas of weakly interacting quarks & gluons
42
30Tg
baryons are a real puzzle…
baryons enhanced for pT < 5 GeV/c
RAA
at high pT v2 reflects opacity of medium
v2
STAR
approximately expected level from jet quenching